The invention concerns a lifting device designed to be mounted on the chassis of a vehicle for loading and unloading the vehicle.
In a known way, the lifting device includes a first arm designed to be articulated to the chassis of the vehicle and, attached thereto, a second arm normally perpendicular to the first arm and ending in a hook for grasping a load.
In a loading configuration the first arm is horizontal and the second arm is vertical.
An arm of this kind is generally designed to engage a ring provided at the top of a load with its hook. The arm, therefore, usually has a length which is slightly less than the height of the load.
These lifting devices are generally mounted on trucks with a cab at the front and in the loading configuration the second arm is disposed behind the cab, above which it sometimes projects.
In order to reduce the overall dimensions of trucks of this kind, in particular for storing them (or to have them adopt a standardized so-called "airborne" format), it has already been proposed to make the upper part of the cab retractable, but projection of the second arm of the lifting device above the cab still remains a problem.
An object of the invention is to alleviate the problem of the second arm extending above the height of the cab of known lifting devices by proposing an adjustable height vertical arm lifting device.